Dakuan/gulp-jest — pull request #4 by jacobstr (2014-12-19 20:49:13+00:00)
Title: Fix for 'no writecb in Transform' error.

The clue came from the discussion here:
https://github.com/rvagg/through2/issues/1

Reproducing:

I'm using gulp-notify and gulp plumber to log errors:

return gulp
.src('__tests__')
.pipe(plumber())
.on("error", notifyError("Jest Error"))
.pipe(jest(packagejson.jest));

This simply might have made the error visible. If a test failed, the callback would be invoked twice.